Every player that is drafted has an ID#. So if a player doesn't have an ID# he will not be drafted. This has been done by the MLB Scouting Bureau.
This would include any player that any MLB club has turned in for the draft. Having an ID# doesn't guarantee that a player will be drafted. Not having an ID# does guarantee that a player will not be drafted. The list is not made public but most eventual draft picks will most likely know.
Often we hear people say things like our son is a 4th to 10th round draft pick. Then we find out he isn't even on the list and will not be drafted.
The individual clubs will have their own draft board, basically the order they think the players will be picked. Seeing that they never know which order players will be selected, they need to be ready to select their highest rated player that is still on the board. But once again every player drafted will have an ID#.
If anyone has ever seen or listened to the actual draft, the first thing announced is the players draft ID#, i.e. Redraft 2033